Weakness of will has perplexed philosophers since Plato's time. This chapter places some of the literature on volitional disorders and addictions in a philosophical context dating back to Plato and Aristotle in an attempt to shed light on issues that a theorist who wishes to analyze the idea of a volitional disorder will face. Key here is the notion of the irresistability and resistability of pertinent desires, which is explored in relation to George Ainslie's work on the ability to make and adhere to personal rules.